Login Issues

i dont know if this bug has happened to anyone of you guys but when i try to login with the the PBE client, i enter my username and password, the league client opens and an error pops up saying "there was an unexpected error with the login.please try again". But when I open the League of Legends Live Servers client and switch region to PBE, this this doesnt happen.
Report as:
Offensive Spam Harassment Incorrect Board